Powerhour

Hey everyone, I'm new this forum but have been on multiple forums before. So here's my question.
i have a 70's 400 b with stock internals (all rebuilt) with a weiand tunnel ran and a "hot" cam as my grandpa say and I want to know what size Holley carb to put on it. And any idea of a ball park hp/tq it will make? Eventually I'd like to have over 400. End goal is close to 500.
ill post some pictures shortly

Iowan

With the information you have given us I'd say about 280 hp and the same for tq, it's a dog.
Bow wow give it a treat.

Powerhour

Powerhour

Darn, 280 is unacceptable haha..define a dog, some dogs are strong and fast while some are weak and slow haha. What could I do to bump it up a bit so I can at least burn some tires..
I pulled a valve cover off and it looks like the casting says 4066452

Iowan

452 is a good head , but yellow paint doesn't make it fast!

Powerhour

hahaha but its adds 20hp right? I personally not a fan of alllll yellow but that can be changed.
what could I do to get a decent bump in power with out completely rebuilding it. ill ask the grandpa what cam is in it again.

Iowan

Sorry but a stock 400 with a cam and a tunnel ram is not xxxx! If you want to make power your going need more.

And its not frickin yellow paint.

Powerhour

yeah the yellow needs to go LOL!
from what I have read, these engines have low compression, so milling and porting the heads, new pistons should make a good bump in the power department correct. (and new color

Iowan

Sorry your post was there before I was done with mine.

The 400 needs compression, 9.5 to 10 / 1 your heads need 2.14/1.81 valves and some mild port work under the valves, if you insist on the tunnel ram two 450 vacuum secondary carbs will do.a 750 DP will work better and make more power.

Powerhour

Thanks for the info!, there is an adapter to convert it to a single carb already on it. im going to be getting it running and driving before I do anything (other then a carb) because the grandpa really wants to go for a ride to before hes not able to.. I do want to start getting the parts together I need for at least 400hp/tq.
I was already leaning on a Holley 750 DP

RacerHog

Whats it going in? Street Rod, Truck, Heavy Car,
If it just been gone threw, Street Blower set up might be rite up your alley?


I would not look for allot of power out of it. But save some penny's and start outing together a 440 Or get some parts together for down the road and build the 400...


Nothing wrong with having fun with what you got...


As for a carb on that tunnel ram... 1-850 Double Pumper should fit the bill.

Powerhour

Thanks for the info guys, it is in a 1947 ford panel, I will be running stock for now as its fresh with about 20 mins of run time. I would like to start getting parts for down the road. a street blower would be amazing but I know I cant just slap one of them on with out doing the supporting work.
Sorry for all of the questions, im fairly new to these blocks

Coronet 500

Can you post the actual full camshaft specifications so we know what we are talking about.

Powerhour

So, I talked to the grandpa and he told me that it is a 3/4 race cam. He's an old hotroder and got it from his buddy who had it before him. So I don't think he knows the cam specs.

Archer

PH -

As has been said, the odds are you don't have enough compression to fully use a "hot" cam (meaning any thing above a 280 duration) and probably won't see enough rpm for the tunnel ram.

If you plan on using/having fun with the car, the first thing I'd do is switch to a decent dual plane 4V manifold and see how the engine responds. A loose converter and gears would help. If you're not happy with the result, you'd have to replace the cam or do a full rebuild.

I'd also loose the yellow paint ...

Archer

RacerHog

Yellow..... I like it... It realllllly stands out....

Iowan

Or you could tun what you have, have fun NOT worry about the HP number. That's what I would do.

Try a 750 BP Holley , I would hope you have a 3.91 or deeper gear and a converter with a 3000 stall because you might be looking at an off idle stumble.

The yellows fun i now a mopar racer that paints his 440s purple

Georges

hello everybody, i have a dodge challenger 2015 SRT 392 6,4l, and there is ticking noise during acceleration, its my daily drivable car and the noise is annoying
is it dangerous ? My car have only 20000 km

Powerhour

I definitely am going to run it as is, I just want to make it perform like it is so I might have to rework the heads. I want to leave the cam in it and the tunnel Ram as that's how the grandpa wanted to build it( he is getting to old to build hotrods so I'm building it for him)

Archer

PH -

Find or figure out the specs on the cam, without that, you're flying blind. Then you have to build up the compression. I would look into aftermarket aluminum heads, with smaller combustion chambers as the easiest route.

Now, don't get us wrong. Almost any configuration you have will/can work with a little tweaking. That might be all you want/need. To make the engine / car run as efficiently as possible, then you have to rethink. No right or wrong, but know what you're getting yourself into.

Archer

Powerhour

I will figure out how to get the specs on it. the Gramps doesn't know lol

Archer

PH -

You could get creative and read the valve or push rod travel. Just remember that std rockers are 1.5:1.

Archer

Powerhour

Hey guys, so I found a local shop that can re-work my heads, at that time I will send my cam shaft to get properly measured (me and my step dad can get the lift durations in the next few days) what would be a good recommendation on these heads? I know I need to mill them down and port them out, but what are your guys rec's?

Iowan

The last set of 452s I did I cut them until I got 80cc in the combustion chamber, I can't tell you how much you need to remove because each head is different. But that's the goal, 80cc.

For the porting mopar performance, Direct connection used to have templates for the bowl work, I've heard that there online and you can print them off. The biggest thing is do not get carried away.
Just unshroud the valves and blend the bowels

Find some videos on head porting and if it's not something that your comfortable doing don't because you can turn good heads into junk. But on the other hand the 452 head will, if done correctly support over 500 hp.

Powerhour

Thanks Iowan! I've done lots of metal work in the past and I have diegrinders so I'm fairly comfortable doing that if I have a template (I have OCD so I work slow and carefully) so for me massaging the ports I'll save some coin. Do I need new valves/ springs if I'm only doing a small port?

Iowan

Not necessarily, you can port with stock valves, but I would use 1.81/ 2.14 SS valves.

Iowan

Your going to need stones and flapper strips, Mr Gasket makes a nice kit.

Archer

PH -

Find out the cam specs first. If you plan on staying with that cam, that will dictate the optimal head specs.

Archer

Iowan

You will need to be careful about your build, some people will tell you how to build your 400 but can't tell you how to blue print your oil pump! Just saying.

Iowan

Personally I like iron headed big blocks, if you can do the work you earn the HP, any smuck can buy a set of head's.

I have a 500" 440 with 915s that makes 645 HP, so kis my butt!

Aluminum head's are for those that can't do ****!!!!